Hardwood flooring generally consists of a number of juxtaposed elongated tongue-and-groove planks P (FIG. 1) interlocked with each other, and then fastened in position to a subjacent subfloor S. To fasten these hardwood planks P to the subfloor S of a room (composed for example of plywood plates and/or floor joists), it is known to use a dedicated pneumatic nailer N, N′, N″ (FIGS. 1-3). A pneumatic nailer for hardwood flooring generally comprises a main frame carrying a floor-engageable shoe H mounted to its bottom surface, upon which the nailer rests against a hardwood plank prior to discharging a fastener in the latter.
The pneumatic nailer also comprises an actuator housing on the nailer's main body and connected to a pressurized air source (e.g. an air compressor). The actuator housing has a casing defining a pressurized air chamber therein, the casing carrying a fastener discharge mechanism comprising an actuator head and a piston assembly. The piston assembly comprises a cylinder defining a cylinder chamber, and a plunger mounted inside the cylinder chamber and movable therein between upper and lower limit positions. The plunger in turn comprises a head portion engaging the inner peripheral wall of the cylinder in airtight fashion, and a striking rod carried by the plunger head.
At rest, a valve of the actuator head is positioned in a closed position, in which it cuts off fluid communication between the upper portion of the piston's cylinder chamber (the portion located above the plunger head) and the pressurized air chamber. To conventionally set off a fastener discharge cycle of the nailer, a workman activates a trigger thereof, which causes the valve to shift to its open position and to enable air to be admitted in the piston's cylinder above of the plunger head, which causes the plunger to move with great force and celerity from its upper limit position to its bottom limit position. As the plunger travels from its upper to its bottom limit position, the striking rod thereof sweeps the fastener ejection channel containing a fastener. The fastener is consequently forced out of the nailer and driven into the subjacent workpiece.
Moreover, a magazine M (M′, M″) is usually mounted to the nailer and serially feeds fasteners, grouped in a strip of successive fasteners with frangible interconnection between each successive pair of fasteners, and each fastener individually in the form of metallic L- or T-shaped barbed cleats or staples, one at a time into a fastener ejection channel defined by the actuator housing and proximate bottom shoe H.
Current state of the art fastener strips number is 100 fasteners, for 16 ga nails, 120 fasteners for 18 ga nails, and 46 fasteners for staples. The size and shape of the fasteners must be compatible with the structure of the storage chamber inside the magazine. Inside the magazine, there is a linear blade biasing means to bias the leading fastener from the strip of fasteners toward the strike channel. Usually, as shown in FIG. 1, magazine M is straight and extends in upwardly outwardly inclined fashion relative to a vertical plane intersecting the nailer shoe H in the nailer operative condition, and perpendicular to the fastener ejection channel.
Simply extending the length of a fastener magazine M to load additional fasteners has a number of drawbacks, including:                it keeps the tool N away from the work area due to its size;        it brings improper center of gravity shift problems;        it increases minimum horizontal clearance values, thus preventing a nailer operator to nail several rows of wooden planks close to an upright wall W (FIG. 1) which would otherwise have been nailed;        a nailer N is designed in such a way that by lifting its top handle D, the bottom shoe H and the fastener ejection point all take their operative positions; this is not possible when a nailer fastener magazine M is of greater length, since the operator must then provide constant wrist rotational torque to compensate unbalanced center of gravity and to provide suitable tool positioning, thus bringing muscular fatigue to the operator.        
In conventional fastener nailers (illustrated in FIGS. 1-3), the magazine M must always be longer than the total length of the combined load of multiple fastener strips engaged in the magazine channel. Moreover, a further drawback of conventional fastener pushers U (FIGS. 8-10) is that they are not adapted to operate in an elbowed magazine channel environment.
One could operate without pusher U, and let fasteners be fed by gravity. However, typically, one problem with gravity feeding of fasteners in a nailer magazine M, M′, M″, is the jamming that occurs when only a few fasteners remain in the magazine.